In the prior art, there are various arrangements for slowly metering out dry material held in bulk form in feed bins. One of the more common devices used for this purpose is an auger. Typically, the feed bin includes a generally rectangular compartment which tapers downwardly in a V-like cross-sectional shape into a discharge tube or other arrangement for containing an auger. Thus, the auger flight is exposed to the dry material in the bin along the top of the discharge tube and at the apex of the V such that the auger flight captures the dry material and, as the auger drive motor is operated, conveys the dry material to the end of the discharge tube where it exits therefrom in a discharge opening into a hopper of some sort. In a batch weighing device commonly used in the prior art, a weigh hopper is mounted beneath the discharge tube opening, and one or more banks of feed bins and augers are mounted on either side thereof for conveniently conveying different quantities of different materials into the weigh hopper as required to make up a batch of material for use in a process.
In the prior art, there are many arrangements for these augers including their drive motors. However, for the most part, and as best known to the inventor herein, little attention has been paid to the problem of removing the auger from the discharge tube in order to clean out the feed bin. Still another problem typically experienced in the prior art is that the auger flight, which extends in cantilever fashion from the drive motor, is typically permitted to rest directly on the bottom of the discharge tube so that the auger flight invariably has a tendency to scrape or shave metal filings away from the bottom of the discharge tube. This problem results from the auger flight not being supported at both its inboard and outboard end by a suitable bearing so as to center the auger flight within the discharge tube and prevent its overhung weight from loading the outboard end of the auger flight. Furthermore, not only will the weight and loading of the auger flight contribute to this problem, but the mere fact that the auger flight is permitted to "float" within the discharge tube results in eventual wearing of the discharge tube and increased problems in this regard. While many of these feed bins and auger drives are utilized in processes where generally de minimis amounts of metal filings and shavings do not appreciably detract from the results of the process, there are some applications which require higher standards of cleanliness, purity and the like such as in processes where food stuffs are the end result thereof. These applications require not only that the metal filings and shavings typically experienced in the prior art devices be eliminated, but also require that the feed mill and auger drive be arranged to meet the FDA standards of cleanability and the like on a regular on-going basis. This requires virtually complete disassembly and separation of the auger from the feed mill and complete access to the discharge tube for flushing. Therefore, in these applications, the auger and feed bin arrangement must be suitable for rapid disassembly and reassembly but also provide for adequate support for the auger flight both at its inboard and outboard end. The inventor is aware of no arrangements for augers and feed bins which are particularly directed and adapted to this problem.
In order to solve these and other problems in the prior art, the inventor herein has succeeded in designing and developing an auger which not only provides both inboard and outboard bearing support for its auger flight as mounted in the discharge tube, but also may be removed by quickly disassembling a mounting plate and flange secured with a few bolts. The auger flight, which extends through the discharge tube, may then be quickly and conveniently removed and/or reinserted from the discharge tube. Furthermore, by providing a notch-like discharge opening which is spaced inwardly from the edge of the discharge tube, a lip is formed which may be used to support a bearing rotatably mounted to the end of the shaft which supports the auger flight. Thusly, the outboard end of the auger flight is conveniently supported by a bearing which eliminates the problem of metal shavings contaminating the material being processed through the auger. The mounting plate and flange may be conveniently located at the outboard end of the discharge tube such that it is readily accessible by maintenance personnel. This is especially an advantage where a plurality of feed bins and augers are rack mounted along a batch weighing device or the like such that a maintenance man may step from one feed bin to the next and with a socket wrench or the like quickly and easily remove the four or so bolts which mount the auger assembly to the feed bin and then slide the auger flight out of the discharge tube. In this manner, all of the augers may be conveniently removed from the feed bins of a batch weighing device or the like such that the entire device may be washed down in one process. Thereafter, all of the augers may then be quickly and conveniently reassembled to the feed bins in a minimal amount of time.
As explained above, an outboard bearing assembly may be rotatably mounted to the end of the shaft which carries the auger flight. This bearing assembly may be made of a self-lubricating plastic which is relatively inexpensive and yet which facilitates the insertion or removal of the bearing from within the discharge tube. As can be appreciated, the bracket is generally annular in shape and must be pushed or pulled through the discharge tube in an axial direction which might otherwise have a tendency to cant the bearing, leading to jamming and potentially damage to the bearing, shaft, or discharge tube. By utilizing a self-lubricating plastic material as is well known in the art, these difficulties are eliminates and a smooth insertion and/or removal of the bearing may be readily achieved.
The modular nature of the auger assembly also renders it convenient for troubleshooting and/or maintenance with minimal down time to the batch weighing device. As can be appreciated, a batch weighing apparatus typically represents a significant capital expenditure and, perhaps more importantly, is often an integral portion of an on-line process. Therefore, if a particular auger drive, auger flight, bearing, or some other component of the auger fails or otherwise requires maintenance, the inventor's design provides for a quick and convenient way to replace the entire auger and thereby eliminate whatever problem existed in the auger which may have led to a malfunction. Furthermore, the different components comprising the auger, i.e. the drive motor, coupling, bearings, and auger flight, are all readily replaceable with minimal disassembly such that a minimal amount of spare parts are required to support the multiple number of augers typically found in a single batch weighing apparatus, Therefore, the modular design of the present invention also provides increased advantages and convenience over the prior art for these reasons as well.
While the principal advantages and features of the present invention have been described above, a more complete and thorough understanding of the invention may be attained by referring to the drawings and description of the preferred embodiment which follow.